He has denied any involvement in the attack which killed about 20 people.
In Summary
• Last November, gunmen broke into a military armoury and several prisons in Freetown, freeing almost 2,000 inmates.
• West African leaders have been trying to broker a deal for Mr Koroma to move to Nigeria in return for the charges being dropped.
Former Sierra Leone President Ernest Bai Koroma has been charged with four counts of treason in connection with an attempted coup.
Last November, gunmen broke into a military armoury and several prisons in Freetown, freeing almost 2,000 inmates.
He has denied any involvement in the attack which killed about 20 people.
West African leaders have been trying to broker a deal for Mr Koroma to move to Nigeria in return for the charges being dropped, the BBC understands.
The BBC has seen a letter saying Mr Koroma has agreed to the deal, brokered by the regional group, Ecowas.
However, it is not clear whether Sierra Leone’s President Julius Maada Bio has given his approval.
Some of Mr Koroma’s supporters cried in court as the charges were read out, according to the Reuters news agency.
On Tuesday, 12 other people were charged over the attempted coup, including one of Mr Koroma’s former bodyguards.
The former president’s daughter, Dankay Koroma, has previously been named on a list of wanted suspects by police. She has not commented.
